Huge amount of keratinous waste, especially birds’ feathers, demands more value-added application instead of dumping. The present work reports the results of experiments aimed at preparing soluble keratin useful for novel bioproduct formation. The effect of thermo-chemical treatments with various reducing agents, i.e. 2-mercaptoethanol, dithiothreitol, sodium m-bisulphite, and sodium bisulphite, as well as sodium hydroxide, on the yield of keratin extracted from chicken feathers was determined. It was shown that after 2-h reduction with 2-mercaptoethanol and sodium bisulphite, the yield of soluble keratin was about equal and amounted to 84 and 82 %, respectively. The cheaper and harmless sodium bisulphite additionally decreased the extraction time to 1 h with the same yield. Moreover, treatment of the feathers with 2.5 % NaOH further improved the extraction effectiveness by increasing the yield up to 94 %. The results of the study demonstrate the viability of hydrolytic processes to obtain soluble keratin useful for biodegradable film formation for food application, that are harmless and more effective than solubilization by reduction of the disulphide bonds.

Bacterial nanocellulose (BNC) is a natural biomaterial with a wide range of biomedical applications. BNC contains 99 % of water which makes it too thick to be used as a bioimplant material. The aim of the work was to determine the effect of the BNC dehydration followed by rehydration on its mechanical and physicochemical properties, in the context of the use of BNC as bio-prostheses in the cardiovascular system. Dehydration involved the convection-drying at 25 and 105 °C, and the freeze-drying, while rehydration - the soaking in water. All modified BNC samples had reduced thickness, and results obtained from FT-IR, XRD, and SEM analysis revealed that 25 °C BNC convection-dried after soaking in water was characterized by the highest: tensile strength (17.4 MPa), thermal stability (253 °C), dry mass content (4.34 %) and I_α/I_β ratio (1.10). Therefore, 25 °C convection-dried BNC followed by soaking in water can be considered as a material suitable for cardiovascular implants.